Photographic enlarger



Sept 9 1941-l M. B. KANTER,

PHOTOGRAPHIC ENLARGEF.

Filed Aug. l2, 1939 2 Sheets-Sheet l 5 i-- ma! y #fon @an n LLQKOIM CTTocmEp/S Sept 9, 1941 M. B. KANTER 2,255,319

PHOTOGRAPHIC ENLARGEF.

Filed Aug. 12, 1939 2 sheets-sheet 2 od'romays Patented Sept. 9, 1194i UNITED STATES l PATENT OFFICE 2,255,319 rnoroonsrnro Emnosn Milam n. meer, chicago, nl.

' Application sans: 12, 1939, serial No. 289,755

The present invention relates to improvements in photographic enlargers.

One general object of the invention is to provide an improved enlarger of such character as to simplify the task of inserting and removing negatives or illms during the use of the device, as well as to simplify the process of masking o!! or cropping o! desired portions of the negative. l A more specio object is to provide an enlarger embodying a relatively movable lamp housing assembly and negative carrier between which a nlm may besandwichel and clamped in position simply by the pressure of the opposed portions of the assembly and carrier when they are moved together but of such character, however, that even when the negative is clamped it may be freely rotated about an axis parailelling the light path through it in order to change the angular position of the projected image Another and important object of the invention is to provide in a device of the character indlcated a novel masking l assembly adapted to carry a negative which is to be enlarged and by means of which the negative can be masked any desired amount and adjusted in angular position, all by means of very simple manipulative operations,

The invention also resides in various struotural improvements in the device by virtue oi which low cost of marini-settare is combined with ease manipulation end operation as well as ruggeiineee censiti ion.

not Sie objects and edventages of the invenm tion will become apparent es the following clescription prooeeds, taken in connection with the accompanying drawings in which:

Figure l is a side elevation, partly in section,

of a photographic enlarger embodying the in eluded in the assembly of Fig. 5.

For purposes of exempliilcation the invention bodied in an enlarger (Fig. 1) which is especially adapted for use by amateur photographers.

It will be apparent to those skilled in the art,

however, that the invention is applicable to a 5 large variety of specific forms of enlargers. Accordingly, even though one particular embodiment of the vinvention has been shown and described in some detail, there is no intention to thereby limit the invention tovsuch embodiment, but on the other hand the appended claims are intended tol cover all modifications and alterna.- tive constructions falling within the-spirit and scope 'of the invention.

In the illustrative enlarger (Fig. 1) the optical system oi the instrument includes an electric lamp i as a source of light, the usual coni densinglenses ii and i2 (Fig. 3) arranged in a casing section or'extension i3 at the lower end -of the lamp housing iii '(Fig. i), and an enlarging camera including a cropping mask assembly designated generally by the numeral I5 and the usual enlarging lens it carried on a lens mount I I? at the lower end oi an extensible bellows i8. Light emitted from the lamp iii is applied by the eondensing lenses li. to a negative i9 sandwiched between the lamp housing assembly a glass negative carrier plate or platform 2@ forms the top of 'the eroppine mask as i@ (see sieh I image en the .tive i is thus j ojeoted enlarged iorni e Tiens i6, on

e inode of optieai system the conse@ seerd is bell 'rrr .s .ezel-te and snnplic henry; ci inserting removing the negatives che 'terme the present enlarger. To the heee. le i@ in instrument, the lamp housing iid is raised to espose the top of the carrier E@ and the negative laid on this carrier, The lamp housine' is then lowered so the bottom condensing lens i2, which is fioatingly mounted a manner hereinafter de-v scribed, rests on the negative and presses it flat against 'the ceriier 2b. riiierceater the angular position si the negative andA the portion of it to be exposed can be easily adjusted by means of the cropping mask assembly i5, as is also here inafter explained.

The upper condensing lens il is carried in a cylindrical sheet metal holder 22 (Fig. 3), being v arranged to rest on an annular bead 23 formed l in the side wall of the holder. The inwardly has'been shown and, described herein as em- 55 curled lower edge of this holder 22 in turn rests on a shoulder 2d fashioned in the side wall of the casing section I3. The lower edge of the casing section I3 is inturned as indicated at 25 at an angle complemental to a bevel 26 on the lower condensing lens I2 so that this lens is freely or oatingly mounted in the bottom of the casing I3. Consequently, when the lamp housing assembly It is lowered the bottom condensing lens I2 finally comes to rest on the negative I9 and the weight of this large condensing lens holds the negative securely in place. It will be -noted that the casing section I3 is telescoped over the lower end of a tubular outer wall or casing 2l of the lamp housing proper, in which position it is removably held by screws 28 (Fig. l). It will thus be seen that to remove the condensing lenses II and I2 the casing I3 is first taken on and the carrier 22 lifted out of it, whereupon the two lenses may be removed respectively from the holder 22 and casing I3.

Raising and lowering of the lamp housing i4 for clamping and unclamping of negative I9 is accomplished by means of a rack and pinion mounting for the lamp housing. The housing I i itself is of the usual double-walled air-cooled sheet metal construction being generally cylindrical` in shape. Cooling air enters the space between the inner and outer housing wallsy through holes 29 (Fig. l) in the outer casing 2l, circulates upward by convection and is discharged through holes 30 in a sheet metal cover 3i telescoped over the'top of the casing 2i. On

having notched guide projections 33 which embrace a corner of a stationary vertical rod 3d, the latter being square in cross section. The

'arms of a U-shaped projection 35 on the bracket 32 extend on each side of the rod' 3d, and in notches 36 (Fig. 4) in the outer ends of these arms is journaled a pinion 3l meshing with rack teeth 38 fashioned on the rear edge of the rod 34. The shaft carrying the pinion @l is held in the notches 3o by spring pressure straps 39 screwed to the outer ends of the arms 35. These pressure straps or bands also serve'to urge the pinion 3l inward into firm frictional engagement with the rack teeth t so as to prevent inadvertent gravitational descent of the lamp housing I 4i. To move the lamp housing up and down theoperator need only turn a knob t@ on the projecting end of the shaft to which the pinion 3l is fixed. As a further aid in guiding the pinion along the rack two opposed guides the side of the casing 2l is fixed a bracket 32 camera carried by it. hus the rod 34 is xed to a bracket fil which extends from a sleeve :i8 that is slidable vertically on a post (i9. This post is angularly adjustable in avbase socket 50 to which the baseboard ZI is also fixed. A rack 5I is fixed to the side of the post 69 and a pinion 52, carried by shaft 53 journaled on a sleevell, meshes with this rack. The pinion 52 is urged .into engagement with the rack 5I by spring pressure straps 54 just as in the case of the pinion '37. previously described. 1

To raise and lower the sleeve d8, and accordingly all of the parts carried on the rod 3d, the operator need only rotate the pinion shaft 53. To facilitate this adjustment the shaft 53 is extended to the front of the machine and a hand knob 55 provided on its forward end. AThe intermediate portion of this shaft is journaled on the bracket 41 at 56.

Of particular importance in the enlarger is the novel 'cropping mask assembly I5, heretofore generally noted. This assembly is preferably removable as a unit from the rest of the apparatus for the sake of simplicity in cleaning and inspection. In brief, it includes on its top surface a negative carrier, shown as the glass plate 20, together with means below this plate forming an aperture of adjustable size. By adjusting the size of the aperture beneath the negative I9, theaperture can be made to fit exactly a film of any desired size up to the full dimensions of the aperture and alternatively desired portions of' a negative can be masked off or cropped The assembly I5 is arranged for swiveling motion about a vertical axis so as to adjust the angular position of the negative relative to the sensitized paper on which it is projected. Both the aperture size adjustment and angular adjust.-

Aof the maximum size of film area that can be enlarged inthe device. To the lower side of this plate 5l is fixed the bellows I8 by; a suitable light-tight connection.

III of truncated cone shape are fixed to the opposite ends of the pinion Sli and engage the opposed side surfaces of the rod or bar 3d.

For the sake of simplicity in construction a second series of rack teeth d2 (Fig. 1), also fashioned on the rod 3s, is utilized-as part of a rack and pinion adjustment mechanism for focusing the instrument. For this purpose the lens mount I'I on the lower end of the bellows I@ is fixed toV a bracket 43 having a U-shaped end M 'slidably engaged with the rod 3. Between the The mask assembly itself comprises a sheet metal bottom plate or mask 5S (Fig. 9) having a central aperture d@ of the same dimensions as the aperture die in the supporting plate 51 (see Fig. 2). Four corner studs @I screwed to the mask 59 -(Fig. 6) are slotted to receive the glass cover plate or negative carrier 20 of the mask assembly. This glass cover plate can be slid longitudinally out of' the supporting slots for cleaning and the like. vThe `cover plate 2u and bottom plate 5@ are thus mounted in closely spaced parallel relation with room between them for means to vary the effective area of the aperture Si) as described below.

In order to vary the effective area of the aperture in the mask assembly I5 two pairs of adjust- A second hand wheel or knob 66 conof the lens I6 from the baseboard 2| for focusing,

able blades 62 and-63 are slidably mounted between the opposed faces of the top and bottom plates 20 and 59. These blades are opaque, being preferably fashioned as stampings from sheet metal such as spring steel. The respective pairs of blades are arranged at right angles to each other with the blades in each pair having Atheir edges opposed and generally parallel. The end portions oi each oi the blades is bent down in offset relation so as to engage the adjacent edge of the mask or bottom plate 59 to guide the blades for movement across the base of the mask. The projecting ends of the blades form convenient finger grips for manipulating them, that is, sliding them back and forth across the aperture $0. The edge portions of the blades adjacent the studs 6I are notched (Fig. 5) to facilitate displacement of the blades a suillcient distance away from they center of the mask l! to entirely clear aperture 6 0 when the blades are completely retracted. Bosses 64 struck up from the upper sides of the blades 62 and 6I are urged into engagement with the under surface of the glass cover plate 20 by the resiliency of the sheet metal Iblades so as to hold the blades frictionally in adjusted position.

It will be apparent that with the arrangement described the two pairs of blades Bland 83 can be adjusted toward and away from each other in order to cover any desired portions of the aperture in the main mask 58 and to leave an eifec,

tive aperture of a size matching any desired size of film up to the maximum area of the-aperture SII. Furthermore, the blades can be untilized to mask oil* or. crop any desired portion of the negative or illm resting on the cover plate 20 above the aperture i0.

To make possible angular adjustment oirthe mask assembly I a circular groove 65 (Figli. 2

Having inserted the' negative I 3 the operator focuses the enlarger by turning the knob li to raise or lower-the lens I 6. When focusing on a sensitized paper a red fllter 'I4 (Fig. l), swiveled in a bracket arm 1i, is swung into place to intercept the light beam. After properly focusing the instrument the operator grasps the ends of the masking blades 62, 63 (Fig. 5) and either adjusts them to border the particular size of negative being used or to mask off part of it, just as may be desired. For a change in angular position of the negative the operator has only to swivel the masking assembly Ilabout its vertical axis as previously described and without unclamping or removing the negative. All of these manipulations can be carried out so simply and conveniently that the user can devote his full attention to the artistry of his work rather than being disand 5) is fashioned in the upper surface of the` supporting plate 51 with its center at the center of the aperture in the supporting plate. Four small studs 68 on the bottom of the mask 59 are arranged to ride in this groove. Accordingly, the mask assembly I5 canbe swiveled about its center into any selected angular position. In the event that a negative I9 yis clamped on the negative carrier 20 by the lower condensing` lens I2 the negative will, of course, turn with the mask assembly during adjustment of the latters angular position since the bottom condensing lens I2 is fioatlngly mounted and free to turn within the casing I3.

In some instances the operator may Wish to enlarge selected negatives on a reel of film rather than a separate single negative. To facilitate handling of such a reel of film, two reel carriers 6l and 68 (Fig. 2) are provided. These carriers comprise L-shaped rods with their butt ends swiveled in holes in the bracket extension 5b, be-2 ing held in position by set screws da Wig. l.) When not in use the screws E9 are loosened and the carriersswung down out of the way. Collars "Ill, slidable on the carrier rods bindt, and held frictionally in place by .split sleeves 7i, form stops for the reels (not shown) which are iournaled on the carriers.'

In the operation of the eniarger described, the

operator turns the knob 5 to raise the bracket 41 and parts carried by it to approximately the necessary height for the size of enlargement selected. The lamp housing can lbe adjusted for maximum illumination by sliding its supporting` tracted with a multiplicity of mechanical details.

I claim as my invention:

1. In a photographic lenlarger the combination oi' a horizontal negative carrier plate and an underlying apertured mask secured to it in a unitary assembly, means including a oatingly mounted condensing lens arranged above said plate for holding a negative in position on the upper surface of said plate, and means supporting said unitary assembly for swiveling motion about a vertical axis, said floatingly mounted condensing lens serving to hold a negative in place on said cairrier plate during the swiveling motion of the la ter.

2. In a photographic enlarger the combination of an apertured horizontal supporting member, a

horizontal negative carrier plate and an underlying apertured mask secured to it in a unitary assembly, said unitary assembly being carried on said supporting member, a vertically movable lamp housing arranged above said assembly and having a floatingly mounted condensing lens in the lower end thereof, means supporting said lamp housing for vertical movement towarda'nd away from said carrier plate to bring said condensing lensl into and out of clamping engage ment with a negative placed on the upper surface of said carrier plate, an enlarging camera bellows xed to the lower side of said supporting member, and means supporting said unitary assembly on the upper side of said supporting member for swiveling motion about yertieai airis.

3. In a photographic enlarger, the combination ci a horizontal negative carrier and an un= deriying apertured mask secured to in a unitary assembly, means for holding a negative in position en the upper surface said earrier plate, a supporting member arranged beneath said unitary assembly and having a circular groove in its upper surface, and studs uned on the lower side of said mask and arranged ride in said groove to support said unitary assembly for anguin position to press a negative against said plate with the negative sandwiched between the smooth giass surfaces of said lens and piet-e, and adjustable Ameans beneath said plate and separated by the latter from the negative for masking olf selected portions of the negative. 5. In an apparatus oi' the type described a cropping mask assembly comprising a mask ranged with the blades in one pair at right angles to those of the other pair, the blades in each pair being slidable toward'and away from each other to mask oi a desired portion of the aperture in said mask, said blades having abutments thereon urged into frictional engagement with said plate by the resilience ofthe blades to hold them in position, and the blades having projecting ends adapted to be gripped by the user in adjusting their position.

6. In an apparatus of the type described a' cropping mask assembly comprising a mask fashioned of opaque sheet material and having a rectangular central opening therein, studs projecting from the surface of said mask and presenting opposed slots, a glass negative-carrier plate removably mounted in said slots in closely spaced relation to said mask, and a plurality of `away from each other and restraining said elements against swiveling motion about an axis substantially paralleling the light path through said light-passage apertures, a substantially flat negative carrier assembly removably sandwiched between said opposed faces, the latter being movable toward and away from each other on said supporting means for insertion and removal of the carrier, means including intertting parts on said carrier assembly and at least one of said elements for releasably retaining said assembly against lateral displacement while guiding it for swiveling adjustment motion about said axis, and means on the exterior of said assembly and manipulable while the assembly is sandwiched between said elements for swiveling said assembly about said axis without disturbing said elements.

8. In a photographlcenlarger, the combination of a negative carrier assembly of generally thin, fiat configuration, means for clamping a negative across one facel of said assembly, a support presenting a face generally complemental to the other faceI of said assembly, means including a.

generally circular groove in one of said `complemental faces and studs on the other projecting into such groove forming a readily disconnectible connection between the support and assembly for guiding the latter for swiveling adjustment about an axis of rotation substantially normal to the carrier.

MILTON B. KANTER. 

